package com.ding.pc;

/**
 * @author ding
 * @date 2021/7/17 18:33
 * 线程之间的通信问题： 生产者和消费者问题！ 等待唤醒，通知唤醒
 * 线程交替执行 A B 操作同一个变量 num=0
 *
 * A num+1
 * B num-1
 */


public class A {
    public static void main(String[] args) {
        Data data = new Data();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"A").start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"B").start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"C").start();
        new Thread(()->{
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"D").start();
    }

}


class Data {
    private int number = 0;

    //+1
    public synchronized void increment() throws InterruptedException {

        while (number != 0) {
            //等待
            this.wait();

        }
        number++;
        System.out.println(Thread.currentThread().getName()+"=》"+number);
//        通知其他线程，我+1完毕了
        this.notify();
    }

    public synchronized void decrement() throws InterruptedException {
        while (number == 0) {
//            等待
            this.wait();
        }
        number--;
//        通知其他线程，我-1完毕了
        System.out.println(Thread.currentThread().getName()+"=》"+number);

        this.notify();
    }
}